The Gordon Conference on Bacterial Cell Surfaces, to be held in July 1990, is the ninth in a series of productive meetings that bring together outstanding scientists who are using a wide range of approaches to investigate both the structural and the functional aspects of bacterial cell surfaces. The topics that are to be emphasized at this meeting include: 1) interaction of bacteria with other cells and with their environment during both pathogenic and non-pathogenic associations, 2) signal transmission through the envelope, 3) transport of small molecules through the membranes, 4) the regulated and orderly assembly of the constituents of the envelope compartments, 5) the involvement of cell membranes in the mechanism of DNA replication and cell division, and 6) and the function of membranes in energy transduction phenomena. These areas of research are central to the understanding of many basic cellular processes. In addition, the results to be discussed are of direct relevance to medical problems. Not only are bacteria themselves pathogens, but they also provide, through recombinant DNA technology, a means to produce proteins of medical importance. Two sessions of this meeting will be devoted to the mechanism of secretion of protein. Information will be presented that might be used to improve production of valuable genetically-engineered proteins. The atmosphere of the Gordon Conferences is ideal for promoting extensive interaction among scientists. The participants are together for a week in a remote and isolated location. All the meals are taken together and the afternoons are free. Thus, there is ample opportunity for informal discussion. The arrangement is particularly well-suited for the introduction of new investigators into the community of well-established laboratories.